The relationship between systolic blood pressure in the arm and cardiovascular events is well established, and is the basis for modern therapy for hypertension. Such therapy, aimed at reducing brachial systolic pressure, has been very successful in reducing death and disability from cardiovascular events.
However, the brachial systolic and pulse pressure may differ significantly from the corresponding values in the aorta and central arteries. Measurements of central aortic systolic and pulse pressure have been demonstrated as superior to brachial pressure in correlating with severity of existing disease and prediction of subsequent events. Such studies have used direct pressure measurements during cardiac catheterization, or estimates of pressure from the carotid pressure or diameter waveform. Another measurement approach is described in U.S. Pat. No. 5,265,011 to O'Rourke, whereby central systolic and pulse pressure can be determined from a peripheral pressure waveform using a transfer function.
Whilst the latter method has proved highly successful in practice, it requires reasonably complex processing. In order to enable the determination of central aortic systolic and pulse pressure from a peripheral site, using a relatively simple instrument, it would be advantageous to provide a simpler method requiring a less sophisticated processing approach.